<div class="content-l">
  <div class="user-info">
    <div class="avatar"
         (mouseover)="isHidden=false"
         (mouseout)="isHidden=true">
      <img [src]="avatar"
           width="100" height="100">
      <div class="avatar-mask"
           [hidden]="isHidden">更换头像
      </div>
      <input type="file" ngFileSelect
             (uploadOutput)="onUploadOutput($event)"
             [uploadInput]="uploadInput">
    </div>
    <div class="username">{{username}}</div>
  </div>
  <div class="left-nav">
    <a routerLinkActive="active" routerLink="course">我的课程</a>
    <a routerLinkActive="active" routerLink="message">我的消息</a>
    <a routerLinkActive="active" routerLink="comment">我的评论</a>
    <a routerLinkActive="active" routerLink="collection">我的收藏</a>
    <a routerLinkActive="active" routerLink="account">账号管理</a>
  </div>
</div>

<div class="content-r">
  <router-outlet></router-outlet>
</div>
